Determining the population

Ian McNulty

When the Census Bureau releases its latest population estimate for New Orleans in the weeks ahead, it’s sure to be keenly examined by those invested in the city’s ongoing recovery. Estimating the number of people living in New Orleans since it was practically emptied in the aftermath of Hurricane Katrina has been a particularly complex process, and one with high stakes.

Population estimates are used to determine federal allocations that fund city agencies and nonprofits working in education, law enforcement, elderly services and many other areas, says Allison Plyer of the Greater New Orleans Community Data Center.

So when the Census Bureau released an estimate for the city’s mid-2007 population level that the Community Data Center believed was too low, the local nonprofit led the charge to convince the federal agency to revise its figure. The center provided data and analysis at no charge to City Hall, which filed a challenge to the Census estimate that was ultimately approved early in 2009. The result is an increase of nearly 50,000 people over the previous estimate, bringing the city’s official head count to 288,113 as of July 2007. Plyer calculated that with the increased estimate the city stands to gain an addition $45.6 million in federal funding. “What’s also really important, but hard to quantify, is that private business decisions are based on population estimates,” she says. “It affects decisions of hospitals to open here, or stores, or conventions to book here. Even advertisers gauge what a market is worth using these numbers, and that’s important to the Saints and Hornets.”

There is no comparable modern example to the speed and sweep of dislocation Katrina caused, so trying to track population changes on this scale is taking demographers into uncharted territory. The Census estimates are based primarily on federal tax filings, but that’s a problematic method here, Plyer says. Many poor people don’t file tax returns, for instance, and young, highly mobile professionals often file from their parents’ home addresses until they settle in. Undocumented immigrants present another issue. For its challenge, the center included data on local utility accounts, building permits and mail service to capture a broader portion of residents.

When the latest population estimate is issued later this season, the Community Data Center expects an increase of about 6 percent over the recently revised number. If it’s less than that increase, Plyer says, the group will likely challenge the estimate yet again.